A Friend Given By Nature
by blackmoon9793
Summary: Sarah realizes just how much she's always wanted a big brother. 3x10


_Here's another commercial break plot bunny, this time to explain what the heck happened to Mark after the third season finale. Fingers crossed he and Gracie will be back for the last season and we'll get something along these lines for him and Sarah._

 **Disclaimer: It took me an embarrassingly long three and a half months to write eight thousand words. There's no way BBC America or Space would have anything to do with me.**

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 _Un frère est un ami donné par la nature._ — Jean-Baptiste Legouvé

* * *

She recognizes the look in his eyes when she tells him he's done the right thing. The knowledge she's right tempered by knowing nothing can ever make him feel it is so. Sarah is intimately familiar with that contradiction.

Mark barely meets her eye and refuses to acknowledge any of the others. His gaze lingers on Kendall for less than a second before he turns away, the back of his left shoulder the only indication he's still listening as he pulls the ill-fitting cap from his tousled hair.

As difficult as it has been for Sarah to accept their original, she knows it must be even more unsettling for Mark. This hard, volatile old woman could not have been what he imagined. He had probably never considered that he might have come from a woman. Had he dreamed of this person all his life, just as she had had since learning of their convoluted origins? Had he been waiting for the same thing, the same person she had been looking for all her life?

Mrs S speaks behind her, pulling her back to the task at hand. "What's your plan, Sarah?"

She looks at her over her right shoulder, her body still angled toward Mark. "There's nothing to do but wait. Ferdinand agreed to send confirmation when he has Cody. We'll hold tight and go from there."

"We should take him back," Felix says, arms folded tightly over his narrow chest, only conceding the other man's presence with a swift shift of his eyes.

"No," Sarah responses, too quick to her own ears. "No, not yet. I want to make sure everything goes to plan with Helena first."

Felix gives her a look of thinly veiled suspicion and irritation but says nothing, eyes rolling as he pulls his gaze away. Her own eyes flick back to Mark, as they have at least once a minute since Felix kicked down his door. He glances at her, eyes skimming up to their corners, and offers another curt nod before looking away again. He turns his back to the group and begins to walk toward a folding chair beside the steel stairway. He limps still, she notices, as he pulls off the black hoodie.

Kendall grumbles something to Siobhan for the umpteenth time, but Sarah finds her attention stays with Mark. He isn't a large man by any means, but he looks so small as he eases himself down onto that unwelcoming chair, his body curling in on itself, his porcelain face smattered with blood.

The barely-there throbbing in her right knuckles reminds Sarah exactly how that blood came to stain his visage, and she feels her stomach roll painfully at the recollection. They had caused each other so much pain, this brother of hers and she.

He seems so out of place here with her family, her people. His right hand grips the left, his eyes stare at the floor five feet away, as if he's willing his mind elsewhere. He almost assuredly is. And for some reason that thought makes Sarah's heart sink and stomach lurch even more, an inconceivable longing rising like bile in her throat.

She leaves the others, the three generations of her family, to their conversation and enters Kendall's ridiculous biohazard tent; she can't bring herself to care what they must think of what she's doing. Sarah traces the perimeter of the plastic-enshrouded space until she locates Scott's admittedly impressive first aid kit. Hefting it up with one hand, she takes yet another folding chair up in the other and ducks back under the tent flap.

Mark looks up at her when she sits the chair down with a metallic thud and forces the creaking thing to assemble, but just as quickly he tilts his whole head back down, one fist still clenched over the other. Sarah can feel the hush behind her just as distinctly as the three sets of eyes fixed to the back of her head. She brushes the disquiet off, saying nothing, not even looking at Mark as she unlatches the first aid kit at her feet.

His eyes sweep up at the ripping sound that emits from her tearing the wrapper of a sanitary wipe open with her teeth. They move rapidly from her mouth to her eye to her empty hand before he pointedly moves his head to face the wall. "You don't have to do that," he mumbles.

She shakes her head as she carefully unfolds the damp, sterile cloth. "I'm the one who messed it up; I'll be the one to clean it."

He refuses to acknowledge her until the wipe makes contact with his injured skin. Every muscle from his shoulders up flinches. The chair squeals beneath him. "Sarah," he whispers through his teeth, half warning, half pleading.

She raises an eyebrow. "Mark," she counters inflexibly in her best mummy voice.

He doesn't meet her eyes, refuses to, but he stares at the center of her forehead for a full five seconds before his shoulders sag ever so slightly and his gaze moves slowly back to the wall. Sarah allows herself a momentary pique of victory before raising her left hand to press three fingers to the side of his chin, forcing his face to parallel hers as she brings the wipe back to his fragile skin. The muscles beneath her fingers tighten. Mark's eyes slide to focus on the hair resting against her left shoulder, and slowly his grip on his hands loosens until they flex and skid down to rest on his knees. She glances down for a split second when they do. He has such long, thin, pale fingers, so alien and so familiar all at once. She swallows and hopes he doesn't notice her watching him.

They don't speak as she cleans the blood away from his chin, the skin an angry pink even beneath the caked blood. When the wipe soaks pink all the way through she tosses it into a nearby bucket and opens another, not failing to notice how Mark's gaze follows her hands before reverting quickly back to her hair, as though afraid of being caught.

He doesn't react this time when she dabs the cloth against his lower cheek, but when she moves to the spot where the base of his nose meets his upper lip he gives a sudden, hasty hiss and a small lurch, his eyes locking on her. Her hand freezes. He doesn't look away, not even when she whispers, "Sorry."

He waits a beat before responding, "It's alright," in a low murmur. Sarah takes that as acquiescence, and with the barest pressure possible rubs away the dried blood where it pooled at the corner of his nose. He doesn't move, just stares straight ahead, but she can feel the tension in his muscles rolling off of him in waves.

The vermillion crust gives way to the splotchy, lavender skin beneath. Sarah winces, which brings his eyes back to hers, an unspoken question in them. Her mouth twists in a grimace of culpability. "I got you pretty good."

The corner of Mark's mouth twitches, but not in an unpleasant way. "You do have quite the right hook," he agrees, his voice the strongest it has been since he made the phone call.

Sarah snorts. "I'm glad you appreciate it," she says as she resumes wiping his skin clean. "I'm not sure your wife will think so."

Mark chuckles and glances down. "No, I don't suppose she will." He laughs again, this time devoid of mirth. He looks back up and whispers her name. Sarah stills and meets his gaze, waiting.

He licks his cracked lips. "Gracie…she didn't mean anything against you, when she did what she did. For me. I know she wishes it could have gone differently."

But Sarah shakes her head. "I'm not mad at her, Mark." And she isn't, she never was. Truth be told, if she had been in Gracie's position, if she had had to choose between her family and his, she would have sold them out in an instant.

But that doesn't mean it wouldn't have eaten her away inside.

"I understand. I don't blame Gracie, she was just trying to take care of you. It isn't her fault."

Mark shakes his head slightly and looks away, only peeking back at her when she drags the cloth gently along the side of his nose. "You were good to her. You and your family. You took care of her when she needed it most, when I wasn't there for her."

The corners of his eyelids twitch helplessly against their bloodshot charges. Sarah's free hand reaches out blindly of its own accord, her smaller fingers curving around his knuckles. "It's not your fault either, Mark. You were trying to keep her safe."

He shakes his head again, his eyes fixed on their joined hands. "I wasn't there for her when she needed me. She was afraid of me and she ran from me and I let her and it was still my fault she got hurt."

Sarah moves her own head from side to side and grips his hand tighter. "You're not to blame for that either. You had no idea that the mutation was transmittable."

But Mark is shutting down, pulling away from her even as he clutches her fingers to his like a life preserver. "I've put her through so much. I've asked so much of her, so much that I didn't have the right to, that she wasn't prepared to deal with. She deserves so much more than I can give her."

A compulsive wave washes over Sarah to pull him close, to comfort him. For some unfathomable reason, she wants to tell him about Cal, about her lumberjack who gave her her angel baby and was a better parent to her in eight weeks than she had been in eight years. Somehow, she knows Mark would understand what she felt, how her love had become so irrevocably tempered with pain and regret and remorse. He would understand better than anyone else.

But she doesn't. She can't. Instead, she gives his hand another squeeze, says his name firmly, and waits until he looks at her once more. "Gracie was born into a family of Proletheans," she says slowly and decisively, leaving no room for argument. "She was born into this clone mess, she was part of it long before she met you and she would still be on that godforsaken farm if it wasn't for you. You love her, Mark. Loving her saved her more than we ever did."

It isn't necessarily completely true, but Sarah knows she's right. Mark seems to take her speech to heart, as he swallows thickly and nods, his eyes blinking rapidly as he sniffs and looks away. She withdraws her hand back and, after a few seconds, reaches up to resume her cleaning.

"Thank you," Mark whispers just the cloth makes contact with his face. Her hand stills, her mind not knowing what to say, what to do. He isn't looking at her, and the ridiculous feeling that she might cry rears up again. She chokes it down and returns to her task, wordlessly cleaning Mark's nose.

The skin along the bridge is broken underneath the blood splatter, and he gives another short, involuntary protest as the antiseptic comes in contact with the exposed flesh. Sarah mumbles an apology and presses her left hand carefully against his uninjured cheek, holding him still as she wipes the wound she made. The tear is jagged but it isn't deep, and other than the rapidly worsening contusion it doesn't look like she inflicted too much damage. "I don't think it's broken. You're going to have nasty bruise, though."

The corner of his mouth turns up. "It's alright, Sarah. You've done worse."

It's the wrong thing to say, and he realizes it immediately, his face falling as Sarah's does. Her hand falls to her lap, and for the first time since she approached him she finds she can't bear to look at his damaged face.

She had done what she could to put Mark's sins out of her mind in the name of taking down Castor and Dyad, and if she were honest with herself, for one brief, selfish moment, she hadn't wanted even more bad blood with yet another long-lost sibling. And in a way, she's already forgiven him for the ways he had wronged her, because, like his wife, she would have done the same to protect her family.

Which was why she can't dismiss the risk he had posed to Kira. She can understand moving against Leda in the name of Castor, but her daughter is innocent in everything, the most innocent of any of them. For all the steps they had taken toward one another, despite the back and forth they had toyed with since that cold evening in the cornfield, Sarah doesn't know that Mark wouldn't turn on her child. And the very thought of it makes her ill.

He whispers her name again, more exhalation than speech, but when she flicks her eyes back up he's staring unblinkingly at the wall once more. She surveys him unflinchingly, searching for any trace of remorse, of irresolution, but his features don't exude the apathy or hostility she's come to associate with Castor. If she didn't know any better, Sarah would suspect he was, to some extent, ashamed.

She shifts in her chair, purposely exacerbating the tinny squeak to cut the silent gulf between them, and leans forward, clasping her hands in front of her. Sarah wants to stare him down, force him to bow under her authority, her resolve over him, but for some reason she can't. She's tired, so tired, and she's tired of being tired and frightened and lonely. If Mark's response is what she dreads, she doesn't know if she'll be able to swallow down her emotions. So she stares at her hands just as determinedly as he does the peeling paint of the wall.

"Mark," she says quietly, allowing his name to hang in the air between them in the place of his concession. "When I first met you, that night…would you…if you had… _gotten_ Kira, would you have, Jesus, would you have let them do anything to her? Hurt her?"

Her voices wavers slightly as her daughter's name passes over her lips, and with a mild flash of satisfaction she notices his throat bob at the same moment in the periphery of her vision. He stays silent and still as a stone, but from the way his fingernails sink into his palms she knows he's anything but passive. She glances up at him through her tumbling hair; he scrunches his eyes closed.

"I don't know," he mumbles, his voice somehow thick and clear at the same time. "Maybe." His nails dig deeper. "Probably."

It's better than outright confirmation, and, truthfully, Sarah wouldn't have been surprised if it had been, but it strikes a painful chord nonetheless. She nods once to herself and knows it's her turn to say something, to absolve or condemn him, but she misses her cue.

Mark turns to her with no preamble, his body moving to mirror hers as he brittlely uses his bad leg to pivot. "I would have handed the both of you over to Johanssen without a second thought. My mission was to entrench and ingratiate myself with the Proletheans. Whatever they said, whatever they wanted was law up until the moment I found the information he stole from Castor. I would still be with them if it wasn't…if Gracie…"

His knuckles stain white as his voice cuts off. Sarah would feel sorry for him if his reconnaissance hadn't been at Kira's expense.

"I don't –" he starts and stops. "I wouldn't have…done anything to Kira myself, nothing that would have hurt her."

"Would you have stopped Johanssen if he had tried?" Her voice sounds foreign, as if it were coming out of some mouth other than her own.

Mark visibly deflates, his shoulders curling in as his head dips forward, as if to hide from the accusation in her gaze. "I don't know," he whispers, his voice as helpless as it had been in that commandeered basement.

Sarah closes her eyes, suddenly cold. Why, why, why, why, why? Why was this where the trail of her blood had led? It's so impossibly unfair. She wants to be shocked that Mark could be so callous, so unfeeling to a child in the name of protecting his brothers, and it's a greater crime against nature than their creation that she isn't. She wants to run away from him, run away from the tangled web of relation that's been woven between them, but, as always, her need for information overrides her sense of self-preservation.

"Do you regret it?" she asks rigidly, her eyes opening.

Mark's skin turns even more ashen. "I want to."

Sarah wonders, not for the first time, how he is able to live with himself.

His body tightens as he sits up suddenly, his lean frame tilting forward in prostration. "I wouldn't do it now," he insists. "Not now. I couldn't, I just couldn't.

"Sarah," he half demands, half pleads, "I am not going to hurt her. I mean no harm to your daughter. That's not the man I want to be."

She looks back at him, debating. He appears so delicate with his spindly limbs and his too-pale skin and the blood still gracing the upper left quadrant of his face, but Sarah knows exactly how unrepentantly deceptive he can be. That doesn't mean she doesn't want to believe him, though.

His feline eyes don't move as he awaits her judgement. She meets him with equal artlessness. "How am I supposed to trust you, Mark?"

It's not an accusation or a resignation, and Mark understands. "You shouldn't. You're smarter than that, Sarah."

He isn't trying to flatter her or mollify her into placing faith in him. It's a statement of fact: They'll never be able to come to terms with falling on different sides of this battle line. Not completely.

"I'm not going to trust you with her," she tells him with all the steel of a wolf guarding her cub.

"I don't expect you to," he responds with equal frankness. "You don't have to believe me, Sarah, but it doesn't make it any less true. I will never put your daughter in danger again."

"Why?"

He blows a huff of air out through his nose. "Things are different now. I'm different now."

She believes him. The bloodied and determined Mark in front of her isn't the Mark whose face she almost kicked in through the back wall of that diner. He's the Mark who walked away from the Proletheans and the military for a chance at a better life with the girl he loves. He's the Mark who trusted her enough to stick a pair of pliers into his wounded thigh. He's the Mark who offered Paul his support in Mexico. Sarah meant it when she told him she would never have confidence in him where Kira was concerned, but that doesn't mean she believes he'll betray them to Castor. Not after today. He has as much to lose now as she does.

She wants to tell him all this, but the phone in her pocket vibrates before she can go so far as to open her mouth. She pulls it out and opens the message, not failing to notice Mark stiffing and leaning as far back from her as the metal chair will allow, a glaze of dread and resignation falling over his eyes. Sarah reads the text quickly and lets her hand fall to her lap.

Mark blinks twice, nods sharply once, and looks down. "It's done, then?"

Sarah nods in response, a strange tendril of selfishness spoiling her relief. "Ferdinand says he 'has her in custody.'"

He bobs his head up and down once more but gives no further indication of his feelings. Sarah bites the inside of her check, frustrated to no end with her inexplicably soul-deep need to console him. "Mark," she says, leaning forward to recover some of the distance between them, "she isn't dead. Ferdinand isn't going to kill her; she knows too much."

Mark shakes his head, not exasperatedly. "We both know she only has a matter of time." He gives a small sigh and rubs three fingers over the spot where she recalls the bullet having been lodged.

"I'm glad she's been taken down," he says quietly, a note of forced fortitude in his voice. "We would never be safe with her running Castor, pulling Rudy's strings. What she did…to us, to my brothers – she made us less than human. She needed to be stopped before anyone else suffered."

"She was your mother," Sarah says, her hand finding its way to his again. "That counts for something. It's okay to be upset about how this went down."

He stares back at her and twitches his lips sadly. His hand applies the same amount of pressure as hers. "She wasn't a real mother. Everything that's happened has been her fault when it comes down to it. She never told me – I had no clue…Gracie and…and the baby." He breaks off, not emotionally, but just stops speaking. His mouth opens and closes; his larger fingers tighten under hers for half a second. "She took so much from me. I could have done things differently if I had just _known_ , but she never gave me that chance. That isn't how a mother treats her child, it's a science experiment."

"You did the right thing, Mark," Sarah says again, with as much sympathy and resolve as before. It bears repeating.

"I know," he answers this time, and she pulls her hand away because she knows he means it.

The soiled alcohol wipe lies forgotten at her feet. Sarah scoops it up and tosses it into the bucket with the other before taking another from the first aid kit and unwrapping it. Mark doesn't flinch when she presses it to his cheek to finish the job she started.

"Anything from Helena?" he asks.

Sarah shakes her head, rubbing harder against the obstinate blood. "Ferdinand said he's heading to Alison's next to clean up whatever's there."

She says it matter-of-factly but Sarah can't help the twinge of anxiety for her twin that rises from the pit of her stomach. She has no doubt Helena can take Rudy, but as pregnant as she is and psychotic as Rudy behaves…she would feel better if she had heard something by now.

Mark's lips spasm again, and Sarah wonders how burning that particular bridge has affected him. He seemed to trust Rudy even less than Cody, to the point of being as concerned about his potential and penchant for violence as she was. That strange pang of connection that calls out for her to succor him makes itself known again, but Sarah doesn't know how she'll react if Mark exhibits any sort of sadness at Rudy's fall. Rudy, who held a knife to her baby's face; Sarah won't apologize for being glad to be rid of him.

"She'll be fine," Mark says, breaking her out of her reverie. He's looking at her in an unthreateningly appraising way. "Helena. I've seen her take on worse than Rudy. She'll call you soon."

Is he feeling the same way she is? This unbidden and inconceivable sensation that they need to make things right for each other?

Sarah can't bring herself to examine it now, this urgent cry for closeness that's been threatening to suffocate her since she watched Mark desperately pull his wife into his arms mere hours before. Not when he's looking at her like he might just understand the feelings she can't put to words. So she changes the subject.

"You look a lot better than the last time I saw you."

He takes the change of pace in stride. "The bone is still bruised, but my leg is certainly better than it was."

Sarah wipes a long, clean trail up his cheekbone. "Will it always bother you, do you think?"

Mark's eyes lull to the right as she drags the cloth around his left one. "I may always have a bit of a limp. The muscle had to have a couple stitches. But I should still be able to —" he chokes back a whimper as Sarah passes over an open cut over his left eyebrow, somehow managing to disguise his jerk as a cringe. The skin must have split when her fist made contact.

"Sorry," Sarah gasps, her hand recoiling. "Shit Mark, I'm sorry."

He shakes his head, blinking away the moisture forming in the corners of his eyes. "It's okay. It needs cleaning." He leans down slightly, angling his head forward and offering it to Sarah. "Here."

She stares at him, her hand still frozen in place. Mark gestures patiently with his hand. "Go ahead."

Gingerly, Sarah brings the wipe back to his skin, lightly dabbing at the coagulated blood crusting the cut. He doesn't balk, doesn't move a muscle. Her other hand goes to his right cheek, more to steady herself than him. He watches her unwaveringly as she works.

Sarah does everything she can to keep her roiling stomach in check. It isn't the blood – God knows she's no stranger to blood. It's how readily and willingly Mark accepts pain, embracing it as if he's come to envisage it. He probably has. Not for the first time since they've sat down, Sarah has to force herself not to think of the childhood Mark must have endured. Hers had been one of more pain and loneliness than most, but she had also eventually known the love of Felix and Mrs. S. Had anyone really loved Mark when he was a little boy? Had he loved anyone? Or had the people he loved been the ones to teach him only pain is inevitable? Sarah knows she'll never ask him, because she doesn't want to know the answer, but somehow she suspects that if he ever wants to tell her she'll listen to every word.

The cut she's left on him only bleeds a little as she cleans. Sarah chucks the last antiseptic wipe in the bucket and takes her hands away from Mark to lean back over the first aid kit. She rummages through the various plastic containers and cardboard boxes until she finds two butterfly bandages buried in at the bottom under a small ocean of cotton balls. Sitting up, she eyes Mark's laceration as she rips the paper packaging. She doesn't tell him not to move; she knows she doesn't have to.

As she press the first binding into place, Mark quietly begins to speak. "Thank you, Sarah. For this and…and for the last time. Thank you."

She would roll her eyes and call him a shithead and remind him that, this time at least, she had been the one inflicting the damage if he weren't being so unguardedly earnest. His expression doesn't alter as she unwraps the second bandage. "Don't worry about it. It's the least I could do."

Mark gives her a plaintive look that says he would shake his head if she weren't holding it steady. "You didn't have to."

It isn't accusatory or indignant, just a simple and solemn statement of fact. And it strikes Sarah as one of the saddest things she's ever heard, that the only biological brother she has left doesn't imagine he could be able to count on her when he needs her.

"Of course I did," she tries to sound brighter than she feels.

He looks sadly at her through his eyelashes as she positions the adhesive. "No you didn't."

She presses down the last edge of the bandage. "Yes, I did."

He looks down in quiet submission, and she can sense he doesn't want to say anymore on the subject.

Sarah leans back in her chair, her palms moving up and down her thighs. He's going to have to leave soon, she knows, so she tries to memorize everything she can about him. His face is now clean, though by the end of the day it will resemble one of Felix's paintings. He's pale, so much paler than she is. It strikes her suddenly how little they look alike. Where she's soft and curved, he's hard and angular. Where she's warm, he's frigid. His eyes are so very blue, so different from her own. His nose is longer and sharper, his chin stronger. For two halves of the same gene line, they share so little physically. It's unsettlingly distressing.

"You're staring," Mark says quietly, breaking her out of her reverie.

"Just…trying to see the resemblance is all."

He looks back at her intently, his eyes sweeping appraisingly over her face. Was this how she had looked at him? Sarah holds still, instinct telling her to allow him this opportunity. She doesn't breathe, her eyes mirroring his as they whip from one feature to another. Then his roving orbs still, his expression softens. A small smile pulls at his thin lips, as if unsure how it will be received, and he reaches up with his right hand to give her left ear a gentle tug, his thumb grazing her jawbone as it falls away. Sarah smiles back.

Her phone rings in that moment, the artificial chime causing her to jolt back in surprise. A fleeting feeling of disappointment brushes through her again. Mark breaks eye contact with her to look down at the phone resting in her lap. She checks the caller ID and hurries to answer.

"Helena, where are you? Are you okay?"

" _Yes, sestra, it is done."_

Sarah lets out a sigh of relief. She hadn't let herself admit just how worried she had been, regardless of Mark's reassurance. Her sister sounds calm. Mark catches her eye and looks back down at his once-again clasped hands. She can't think about him now, not while she's discussing his brother's fate with Helena.

She sighs into the phone. "But you're alright? You aren't hurt, are you?"

Helena makes a sound that could have been a scoff. _"Of course I am alright, Sarah."_ She drags her sister's name out as if tasting it on her tongue. _"Rudy had the sickness. He did not have much longer anyway."_

"So, is he…?"

" _Dead,"_ Helena interjects, as if trying to help. _"Yes, sestra, Rudy is dead."_ She sounds humbled somehow by that fact, like she's trying to offer due respect to the dead, even if this particular deceased hadn't deserved it.

Sarah's eyes flick to Mark. He's still staring at his hands, trying to look as though he isn't hanging on her every word. She swallows, knowing what the guilt of putting a sibling in their grave feels like. Her phone vibrates once in her hand, indicating she has received another text message. She ignores it.

"Is he still…are you with him now, Helena?"

" _No, Sarah. A small man came with a bald man and took the body from Sestra Alison's garage. The bald one cleaned the floor as well."_

Ferdinand. Sarah pulls her phone from her ear and hastily brings up the text. Sure enough, Ferdinand had notified her that he and his "associate" would dispose of Rudy's corpse and then come for Kendall's samples. They had time. She holds the phone back to her ear.

"— _rah?"_

"I'm here, Helena. Just hold tight, yeah? Wait for Alison and Donnie to get back."

" _No, sestra, Donnie Hendrix found my boyfriend and brought him back from the tow truck wars. I will spend the rest of the day with him."_

Whatever Sarah had expected her to say in response, this certainly was not it. Every thought in her mind is immediately overtaken by the phrases "boyfriend" and "tow truck war." "Wait, what?"

Helena speaks patiently, as if explaining something difficult to a child. _"My boyfriend Jesse Towing is in town. He said we would go for coffee and doughnuts."_

Sarah pinches the bridge of her nose. Never had she ever thought she would be having this conversation with her twin. "Okay. Sure. Just make sure you get back in time for Alison's election dinner tonight."

" _Of course, Sarah. I would not miss dinner with my sestras, not even for Jesse Towing."_

Sarah can't help but smile at Helena's sincerity. "Okay, meathead. And don't forget to get decaf."

" _I know, sestra. Bye-bye."_

"Bye Helena," Sarah says quietly into the phone, but the line already clicked as Helena hung up.

She runs her hands over her face and into her hair, threading her fingers into the thick tresses. When she looks back up Mark is staring at her. He looks undaunted but dejected. Oh Mark.

"Helena's okay, then?" he asks, glancing up at Sarah and back to his hands.

Sarah nods, the relief she feels once again tinged with guilt. "Yeah, she, uh, she took care of everything. She's alright."

He manages to bob his head without lifting it. "Good. That's good. I told you she could handle herself."

Sarah swallows and rests her elbows on her knees, propping the weight of her upper body against them. "Mark, Helena said Rudy was glitching pretty badly. He probably wouldn't have lasted much longer."

Mark leans back in his chair with a metallic shriek, his hand reaching up to rub the back of his neck. He meets Sarah's eyes. "She did him a kindness, then. I've seen what can happen if it's allowed to go on for too long."

His eyes and expression exude honesty, but something in his tone and the set of his jaw tells Sarah some part of him still considers this fratricide. She remembers that feeling, the weight of it pressing down on her heart like a stone. Mark's looking straight into her eyes, but she can tell his mind is in her sister's garage. She exhales all of the air in her body through her nose, her shoulders sagging. The corner of Mark's mouth twitches in what might have been an encouraging smile.

She pitches her voice low so it won't carry. "Mark," she begins, holding his gaze, "you know I shot Helena, right?"

He stares at her unblinkingly for a full two seconds before nodding once, his face giving away nothing. She licks her lips and continues.

"She had just killed our birth mother," Sarah whispers, the pain and anger and confusion of that night still crawling under her skin. "I had no idea that she wouldn't snap and go for me, too. She'd already gotten Kira hit by a car. I…I thought I had done the right thing. At the time…I really believe it was the right thing at the time, and sometimes…sometimes I wonder what I would do now if I was in that situation again."

She closes her eyes for a beat, trying to will away the image of Helena's lifeless, blood-matted head from behind her eyes. When she opens them again, Mark is staring at her expectantly.

"I felt like I had destroyed a part of myself. I was so scared and full of adrenaline that it didn't hit me until later, when I really thought about what I'd done. I thought I would have to live with it, and I kinda had to get used to it, but the aching never completely faded away. It even still comes back to me now every once in a while."

Mark's voice is pointedly void of emotion. "So you're saying I'm never going to stop feeling guilty for killing my brother."

She wants to tell him he didn't kill Rudy, but she knows that even though he didn't do the deed himself he honestly does feel he is responsible, even more responsible than her or Helena.

"I'm saying it's okay to grieve. It's alright to want to mourn him, even if everything he did was horrible. I meant it earlier, Mark, you did the right thing. We all did. But that doesn't mean you're going to completely feel like it was, and that's okay, Mark, it is. I just wanted to make sure you know that."

He's looking at her in a way she recognizes as the way he looked at her as she was stitching the torn flesh from the bullet hole in his leg back together. It hadn't really been that long ago, had it? He doesn't take his eyes from hers. His bright blue orbs implausibly still in that statuesque way of his. His hand inches forward slowly, cautiously, deliberately, even though she's reached for him more than once this afternoon. His fingers are chilled as ever as they wind around hers. "Thank you, Sarah," he says, and she believes he really means it.

"Sarah," Mrs. S's voice calls from across the warehouse, causing the two to pull apart and turn to face her. Sarah feels like slogging herself; she'd completely forgotten where she is and who she's with.

S, Felix, and Kendall have congregated at the other end of the open room, arms folded across their chests in clear reservation. Her mother is giving her a look bordering on impatience. "Was that Helena on the phone?"

Sarah breathes out and wipes a hand from her forehead down her cheek. When had she gotten so exhausted? "Um, yeah, yeah it was. Ferdinand's just been 'round Alison's and should be here in a bit."

"Rudy's dead, then?" Felix asks, his voice completely devoid of sympathy and one brow arched.

Sarah glances quickly over at Mark out of the corner of her eye. He's looking away. "Yeah, it's been taken care of."

"Well, is she alright?" Mrs. S inquires expectantly, ever the mother hen. "Is someone there with her? Does she need one of us to come get her?"

"She's um," Sarah pauses, not quite believing what she's about to say. "She says her boyfriend the tow truck driver is taking her out for doughnuts. I made her promise she'll be back by dinner."

Mrs. S's exclamation of "What?" intermingles with Felix's incredulous "He's real?"

"Wait, you knew about this?" Sarah demands, trying not to sound accusatory, but dear Lord how did _this_ never come up before?

Felix's mouth falls open in indignation, his hands flying to his waist as he cocks his left hip to the side. "Excuse me, how was I supposed to know this bloke actually exists? I thought it was just some of her typical Helena shit."

"I've met him," Mark interjects out of nowhere. "Well, I've seen him. He seems alright."

Every eye in the room swivels to him. Sarah feels her jaw drop partway. " _You've_ met this guy?"

He nods, looking slightly sheepish at the attention from her family.

"When did this happen?"

"When Gracie and I tracked you two out West," he replies, his voice loud enough to carry to the others but directed solely at Sarah. "I was trying to find her at this bar. He seemed nice enough. Maybe not the brightest bulb, but he seemed to genuinely like her."

Sarah's mouth snaps shut as she tilts her head back to stare up at the dilapidated ceiling. Somehow, somewhere, she must have entered one of the parallel universes Fee used to go on about when he drank tequila. Mark, her long-lost clone brother _Mark_ , is giving Helena's boyfriend his approval. How has this become her life?

"The point is," she continues, a note of finality in her tone, "Helena is fine and everything's taken care of on her end."

"So he can go now?" Felix states more than asks, gesturing to Mark with a jerk of his head.

"You don't have to," Sarah says without giving herself time to think, turning quickly to Mark. He gives her a small, empathizing smile that tells her he knows she isn't trying to force him away.

"I need to get going," he tells her softly, leaning back in his folding chair. "Gracie's going to be worrying. I should get back to her."

Sarah can see that he's right. He'll want to be with his wife, to comfort and find comfort in her after the day they've had. And he certainly doesn't need to be around when Ferdinand shows. But Sarah can't help the sudden, curious urge to pull him close and never let him go. The corner of his mouth pulls to the side. He looks back up to Felix.

"Are you driving me back?"

The other man rolls his eyes up and looks like he's trying not to sigh. "I guess," he huffs, his exasperation barely inhibited from crossing the border into rudeness. He walks swiftly across to the stairs with noisy urgency.

Mark turns back to Sarah, his attention on her as they both stand, their chairs scrapping against the concrete floor. She eyes him charily as he unevenly settles his weight on his left leg. It must be tenderer than he's let on.

"What will you do now?" she asks softly as they begin their slow ascent. Her hand moves to his elbow in a silent offer of support.

He rubs his lips together before answering and keeps a steady hand on the railing. "Go West, I think. Far West. Gracie and I should be able to find work somewhere. We'll lie low for a while."

Sarah nods, continuing their measured pace. Of course he won't be staying close by, she'd known he couldn't. Mark will do what she's preparing to do herself with Siobhan and Kendall. That doesn't mean her stomach isn't twisting in knots she isn't willing to untangle.

"Don't be a stranger, Mark."

"I won't," he hastily replies, but the benign expression on his face seems too obligatory for Sarah to think to expect Sunday afternoon check-ins.

"I'm serious," she reiterates as they reach the top of the stairs. She stops at the landing, arms crossing as he moves to collect the windbreaker he had set aside earlier. Before she'd begun throwing punches.

His countenance matches her tone. He stands still for a moment before nodding three times in quick succession. "Okay, Sarah," he says, more unaffectedly this time, as he begins to pull on his jacket.

She can't help the dread she's feeling, the gnawing sensation that she needs to keep him with her, that nothing is settled between them. "Earlier, at the motel –" she starts.

He holds up one besleeved hand. "It's alright, Sarah."

"No," she shakes her head, moving two steps forward. "About…about the glitching. We've got Kendall now. With Cosima and Scott and their science…if there's a cure, they'll find it."

He's holding himself deathly still, looking dead at her, hanging on her every word. Sarah's mouth moves wordlessly twice, searching for words, as he looks like he needs to her hear out in spite of himself.

"Mark," she whispers soberly, desperately, "we're going to figure this out, and I will find you when we do. I'm not going to let that happen to you, I'm not…"

She breaks off, unable to find the words to articulate exactly what she means. She knows she'll never be able to sit back and allow what she had watched happen to Seth, what Helena had witnessed in Rudy, manifest in Mark. Not him. Not this deceptive, suspect, fragile, steadfast, familiar brother of hers. She looks at him helplessly, her inability to offer more reflected in his own visage. But still she doesn't see it coming when he steps forward and wraps his arms around her.

Sarah stiffens as his left hand presses between her shoulder blades, his right arm winding around her to hold her to him. It only takes a second for her to reciprocate, her arms winding around his waist like it's the most natural thing in the world. She takes a step closer and stands on her toes so he doesn't have to bend down to reach her.

She presses her chin into his shoulder. His cheek is resting against the side of her head, just over her right ear. She chokes down her emotions and stares straight ahead, fighting back the urge to cry over the impending loss she can already feel so acutely.

"Little sister," he murmurs into her hair, so softly that she can barely hear, and Sarah realizes in that moment just how much she always wanted a big brother.

Someone to pull her braids and hide her hand-me-down Paddington bear. Who would be embarrassed to be seen with her by his friends while they waited for the bus. Who would help her home when she fell and skinned her knee at the park and let her cry on his shoulder when yet another boyfriend treated her like shit. Who would let her crawl into his bed in the middle of the night when even she didn't know why she was so afraid.

Felix had been her brother for almost as long as she can remember, and she has always loved him as such. But she had always assumed the role of protector, defending him to and from other children and picking him up when he stumbled. There had never been that person for her, someone ready to lend her his bottomless well of strength whenever she needed it. She had needed Mark her whole life, and it's too cruel and unjust for words that she's only just able to see that now that he's leaving her.

She hugs him tighter.

Sarah doesn't know how long they stay like that, but it must be shorter than she thinks. He pulls away first, his hands sliding to her shoulders for one last squeeze. She needlessly straightens the zipper of his jacket and takes a step back of her own.

"Mark," Mrs. S calls from below before either can say anything more. Mark releases Sarah and takes another step away. He looks over her shoulder at her mother, but Sarah keeps her eyes on him, wanting to preserve as much of these last moments as she can.

"Thank you," S says, only a little begrudgingly. "For what you did today. I – we – appreciate it."

Mark nods down at her in acknowledgment, the formality returning. "You're welcome," he says and leaves it at that. His eyes flick farther to his left and his face falls for half a second before he hurriedly looks away. Sarah realizes he must have caught sight of Kendall one final time. There are things he doesn't have the energy to think about either, it seems.

He turns back to face Sarah once more, and she can only look at him. He sighs and shoves his hands into the pockets of his windbreaker. "Goodbye, Sarah."

She tries to give him a sad smile but doesn't quite manage. "Let me know, Mark. Really."

He nods, his lips turning up in what must be a mirror of her own. "I will," he assures her, and she wants so badly to believe him.

Mark rotations and walks carefully to the door. Sarah's eyes shift to Felix, who gives her a cold glare that clearly says he isn't happy about what he's just witnessed and he will be telling her by how much when he returns. She looks away, unprepared and disinclined to deal with Felix on top of everything else in this moment.

On the other side of the threshold, Mark circles around to face her again, hands still in his pockets. "Take care, Sarah," he says.

She raises her right hand slightly in farewell as Felix slides the door closed with a rattling bang.

Sarah's arms drop to her sides, a ragged sigh escaping from deep within her. She leans back against the steel railing, her hands gripping the rusty metal until they turn as pale as Mark's. She closes her eyes, struggling not to drown in the unbearable wave of loneliness that comes crashing down around her.

She wants to be anybody else. She wants to be anywhere else. She wants Kira's steady weight against her chest and her golden brown curls tickling the underside of her chin. She wants Cal's strong, secure arms protecting her and scratchy bear against her cheek and evergreen scent. She wants Helena and Cosima and Alison and Felix's unmarred faces smiling back at her. But in this moment, she really just wants her brother to come back and give her one more hug.

"Sarah," Mrs. S's lilting voice carries up to her. She forces herself to open her eyes. "Are you going to explain to me what all that was about?"

"Not now, S," Sarah calls back, mortified by how close to tears she sounds.

Siobhan leaves her be, for which Sarah is grateful.

She knows she needs to get her mind back on track. They can't afford any missteps, not now, not with Ferdinand. She still has to get through this night.

But Sarah can't help the unnervingly mournful suspicion that she won't be hearing from her big brother again for a very long time.


End file.
